If you wanted to get technical, you could call these "Triple-Butter", but the butter in the title isn't referring to the actual butter used, rather the combination of smooth, creamy peanut butter and a generous handful of butterscotch chips. A bowl and sturdy wooden spoon would work to prepare the dough, but let me suggest using either a stand mixer or hand blender - the dough is fairly thick and stiff, making it a bit difficult to combine without the extra power.
You'll note the use of a couple egg yolks in the cookie base, but don't toss away the whites - you'll be using them separately in a moment. We like the idea of butterscotch and peanut butter playing together, but you don't have to follow suit - instead of butterscotch, think about using bittersweet chocolate chunks or chips, or if you're a real peanut butter hound, peanut butter chips. To keep the theme going, we also tossed in chopped peanuts, but those could just as well be swapped out with say, toasted almonds or pecans. You are really just looking for a bit of texture inside the bars, along with an ingredient that can break up the sweetness.
Scooped into the baking pan and spread smooth, these bars need one more touch before they are ready for the oven. Remember those lone egg whites? The two we saved were whipped into a thick and creamy brown sugar meringue, then spread over the top of the unbaked bars! Seems crazy, but don't think about skipping this - this unique step brings a whole new dimension. The meringue directions did not specify if the whites should reach the stiff peak stage, so I let the meringue beat until it was very thick, glossy and when I turned the bowl upside down, they didn't slide out.
There is one caveat to that topping - it won't be as easy to tell when the bars have baked through since the dough has been hidden. I skipped the toothpick test and followed the time on the recipe, with the note that the top of the meringue to be golden brown. If you do have any doubts on your oven temperature, you may want to check just to be sure.
Left to cool completely, to help your knife glide through the meringue when cutting, give the blade a quick spritz or two with cooking spray. I was going to wait until Jeff got home to give these a try, but the peanut butter scent that wafted off them as they cooled was too much to resist! The bottom of these bars is rich, chewy and fairly dense, while that airy meringue second layer contrasts wonderfully with its light texture. Peanut is definitely the highlighted flavor with the full cup of peanut butter in the bars, along with the crunchy nuts scattered throughout, but I have to say I loved biting into the tear-shaped drops of butterscotch chips too, adding a killer layer of pleasing decadence.